1. Field of the Invention
The present invention relates to image processing apparatuses, image processing methods, noise-amount estimate apparatuses, noise-amount estimate methods, and storage media, and more particularly, to an image processing apparatus, an image processing method, a noise-amount estimate apparatus, a noise-amount estimate method, and a storage medium which allow noise included in data, such as a motion image, to be removed more effectively.
2. Description of the Related Art
In general, data such as transmitted or reproduced image data and sound data includes noise which changes as time elapses. To remove the noise included in the data, there have been known methods in which the average, namely, the whole average, of the whole input data is obtained and in which the average of a part of the input data, which is called a moving average, is obtained.
The method in which the whole average is calculated is effective when the degree of noise included in data, namely, the signal-to-noise ratio (S/N ratio) of the data, is uniform. When the S/N ratio of data varies, however, a portion of the data having a low S/N ratio affects a portion of the data having a high S/N ratio to make it difficult to remove the noise effectively in some cases.
In the method in which the moving average is calculated, since the average of data positioned close to the current input data in the time domain is obtained, the processing result is affected by a change in the S/N ratio of the data. In other words, the processing result has a high SIN ratio for a portion of the data having a high S/N ratio, but the processing result has a low S/N ratio for a portion of the data having a low S/N ratio.
When noise is removed from the data of a motion image, it may be difficult to remove the noise effectively due to movement even if the whole average or the moving average is obtained at a pixel disposed at the same position in each frame.